Machines for tensioning shoe uppers on lasts



April 9, 1968 H. SCHINDLER ET 3,375,592

MACHINES FOR TENSIONING SHOE UPPERS ON LASTS Filed Aug. 30, 1965 UnitedStates Patent 0 3,376,592 MACHINES FOR TENSIONING SHOE UPPERS 0N LASTSHerbert Schindler, Wagenstr. 38, and Karl Stein, Friedrichstrasse 36,both of Pirmasens, Germany Filed Aug. 30, 1965, Ser. No. 483,509 Claimspriority, application Germany, Aug. 28, 1964, Sch 35,700 2 Claims. (Cl.12-113) ABSTRACT OF THE DISCLOSURE A pulling over machine having asupport for a last over which a shoe upper is to be tensioned, gripperscarried on a support and engageable with the lasting margin of theupper, means for moving the last support relatively to the grippersupport, other means for moving the gripper support relatively to thelast support, and means for selectively causing relative movement ofeither the last support or the gripper support to tension the upper.

The present invention relates to machines in which uppers of footwearare stretched and pulled over a last.

On such machines, the last rests on a three-point support or othersuitable support and in one embodiment pincers grip the upper leatherand pull said upper leather downwardly over the stationary last when themachine is actuated. In another embodiment of such machines, the upperleather is engaged in the pincers which are stationary, and the lastsupport is moved upwardly with the last to effect the stretching andpulling of the upper which is held firmly in position by the pincers.

It has been found in practice that either one or the other mode ofoperation will produce a good result, depending on how the model is cut,or whether the last in question is pointed or slightly rounded.

After the stretching of the upper is completed, it is often necessary tocorrect the position of the upper on the last. This is carried out indifferent manner in diiferent machines. In one such machine the entirepincer arrangement is rotated about a central pivot, while in anotherthe position of the pincers can be adjusted individually and separately,and the pull or tension of the individual pincers can be readjustedmanually. However, when the pull for the tensioning of the upper iselfected, the upper leather is stretched tightly over the last, and ittherefore becomes very difiicult to carry out necessary correctionswhich may even result in distortions within the leather structure.

It is an object of the invention to provide a machine which willovercome the above difliculties. More specifically, it is an object ofthe invention to provide a machine capable of operating in either of theabove said modes of operation for the stretching and pulling of theupper on the last.

Another object of the invention is to provide a machine in which theposition of the pincers can easily be adjusted during stretching.

The machine, according to the present invention, is adapted foreffecting either of the aforesaid modes of stretching and turning of theupper, namely, either by the fixing of the last on the last support withdownward pull of the pincers, or by the fixing of the position of thepincers with upward movement of the support and the last. The machineaccording to the invention, therefore, also permits the selectivesuccessive use of the two modes of operation for stretching and pullingthe upper on the shoe last. In addition, the machine according to thepresent invention permits necessary pincer corrections, subsequent tothe stretching of the upper, in an easy and simplified manner, byreleasing the tension in the upper resulting from the stretching priorto the correction by means of a special device therefor.

In a machine of the above type having pincers for engaging an upper on alast to stretch and pull the upper on the last to conform thereto, thereis provided in accordance with the invention a last support which isdisplaceably supported on the machine frame for movement relative to thepincers, and a support for the pincers which is also displaceablysupported on the machine frame but for movement relative to the last,said last and pincers being relatively displace'able to cause an upperplaced on the last to be drawn and pulled thereon.

In further accordance with the invention, the last support and thesupport for the pincers are separately and individually activated byrespective selectively operable drive means. Preferably, each drivemeans is a hydraulic piston and cylinder arrangement operatedselectively by a respective electromagnetic valve.

According to the invention, corrections of the tension of the upperleather can be obtained by the swivelable arrangement of a platecarrying the pincers and by a manually adjustable control lever for thetension of the pincers. This is made possible in accordance with theinvention by the provision of an electric switch for actuating theelectromagnets of the valves, said switch being arranged on the holderof the control le'ver. In one position, said electric switch c auseslowering of the pressure in the cylinders, while in the other positionit restores the pressure. According to the invention, the effecting ofthe different modes of operation of the machine for the stretching andpulling of the upper on the last is achieved by an electric toggleswitch for alternately operating the magnets of the electromagneticvalves.

The invention will next be described in conjunction with the attacheddrawing, the sole figure of which shows diagrammatically in section anembodiment of the invention.

In the drawing, the last rests on a last support 1, the latter beingsecured to a bracket 2 which is guided for displacement in a slide guide3 on the frame 4 of the machine. The bracket 2 is able to move upwardlyin the slide guide 3 by being driven by hydraulic piston 6 and theassociated cylinder 7 by way of an angle lever 5 and a draw or tractionlever 5. The hydraulic piston 6 is actuated by an electromagnetic valve8. After the upper leather has been engaged by the pincers 9 which arefixed on a common base plate 10, the process of stretching and pullingthe upper over the last is initiated by the valve 8, which causes theangle lever 5 and the lever 5' to be actuated by the hydraulic piston 6,whereby the support 1 with bracket 2 is moved upwardly to cause the last17 resting on the support 1 to be thereby pressed upwardly against theupper.

Alternatively, the pincers 9 mounted on the common base plate 10 can bemoved downwardly by a hydraulic piston 11 and a cylinder 12 associatedwith said piston. This motion is controlled by an electromagnetic valve13 associated therewith. Thereby two modes of operation can be effectedfor stretching and pulling the upper over the last. When changing fromone mode to the other, a simple toggle switch (not shown in the drawing)enables switching off one of the valves 8 or 13 and switching on of theother of the valves, so that when valve 8 is inoperative, the support 1remains fixedly positioned on the bracket 2 and the last is able to restthereon so that the pincers 9 can be pulled downwardly with their commonbase plate 10 by the hydraulic piston 11. The operation is reversed whenvalve 8 is operative and valve 13 inoperative insofar that now thepincers are stationary and the last is movable against the upper leatherwhich is engaged in the now stationary pincers.

The correction which may be necessary after the stretching of the upperis completed, is efiected by a regulating or control lever 15 which iscapable of pivoting the base plate 10 which carries the pincers 9. Inorder to facilitate the correction, the pull of the pincers or else theupward pressure of the support 1 is relaxed by operating valve 8 orvalve 13, depending on the mode which has 'been elected, Valve 8 or 13is operated in such a manner that the hydraulic pressure either incylinder 7 or in cylinder 12 is reduced. The control is carried out bymeans of an electric push button 16 which is arranged directly on thehandle 14 of the regulating lever 15. When the push button 16 isreleased, the original pressure in hydraulic cylinder 7 or 12 isrestored at once.

Numerous modifications and variations of the disclosed embodiment willbecome apparent to those skilled in the art, without departing from thescope and spirit of the invention as defined in the attached claims.

What is claimed is:

1. A machine for tensioning a shoe upper on a last, comprising a supportfor the last movable heightwise in the machine, grippers adjacent thelast for engaging the margin of the upper, a support for the grippersmovable heightwise to cause the grippers to tension the upper on thelast, first means for moving the last support in one direction relativeto the gripper support while the grippers hold the upper under tension,second means for moving the gripper support in the opposite directionrelative to the last support to cause the grippers to pull the upper inthat direction over the last, and operator conto the respective cylinderand means for actuating either of said valves with the other valveinoperative.

2 A machine as claimed in claim 1, comprising a con trol lever connectedto the gripper support and actuable to cause movement of the grippersupport for adjusting the angular position of the grippers relative tothe upper on the last, and wherein the actuating means comprises switchmeans mounted on the control lever and connected to the valvescontrolling the fluid pressure in the cylinders associated with the lastsupport and the gripper support, actuation of said switch means causingrelease of the fluid pressure in the selected cylinder to enable the voperator to adjust the upper on the last.

References Cited UNITED STATES PATENTS 2,768,397 10/1956 Jorgensenl211.3 3,022,527 2/1962 Rockwell et al. 1210.1 X 3,060,469 10/1962Diemel et al. l2ll.3 3,157,897 11/1964 Morrill 1210.5

PATRICK D. LAWSON, Primary Examiner.

